Why do we say, mainly in American English, that someone’s green if they’re inexperiened or naïve?
It’s actually quite simple really: it’s because they’re fresh and new, like new green plants growing in the spring. Still, there could be many other adjectives we could use instead of green in this case. I think there’s a particular significance to the way we use green here. Perhaps more than other colours, green has a greater significance than just its surface detail.
A lot of colours have certain connotations. Red means anger, blue means sadness, and so on. As you can see, I’ve written about this before, but I didn’t really think about green that time (I’m thinking about it now because I put on the album Green River before I started writing). I mentioned briefly that it was the colour of the environmental movement, though I suppose thinking now, it’s more than just that. It’s not just a symbol related to the movement. It really directly represents the concept of being environmentally conscious. If we say somthing or someone is green, we usually know straight away that they’re environmentally aware of environmentally friendly.
And yes, it makes sense that we use the colour in this way, because so many plants are green, particularly the ubiquitous grass. But there’s a more fundamental association with nature that I think still exists in the back of our minds somewhere, even if we’re not conscious of it.
You see, the word green can be traced all the way back to the Proto-Indo-European root ghre-, meaning to grow. Green from this developed to refer to the colour of course because it’s the colour of plants growing, particularly grass (which also comes from the same root). In German (grün) and other closely-related languages (think of Grønland) we can see a closer link to the sound of to grow.
Even if we’re not conscious of this (I wasn’t half an hour ago, and still wouldn’t be if I hadn’t felt like listening to CCR while I wrote), I think we still sense it in some way, meaning green is not just a colour, but the very essence of growth, nature, and newness.